The present invention relates to a structure in which the surface of a fine particle or fiber is covered with a monomolecular adsorbed film. More specifically, the present invention seeks to provide a ultra-fine particle stabilized against environment and a highly reliable filler to a synthetic resin.
In a conventional process for producing ultra-fine particles, in general, a metal or metal oxide is evaporated and solidified in a vacuum.
The above process makes the production easy. However, when it is used to produce ultra-fine particles of a metal active to air such as Mg, Al or the like, the particles ignite spontaneously by contact with air and proceed with an oxidation reaction. Thus, the process has a troublesome problem that the particles are dangerous and have a poor shelf life.
In a conventional process for modifying or extending synthetic resins, oxide such as SiO.sub.2, Al.sub.2 O.sub.3, or the like or fine particles or fibers of Fe or Al are dispersed in the resins.
Although the production by the above process is easy, a modifier or extender is merely mixed with the resin, and the product therefore shows a defect that when it is used for a long period of time, a material of the resin is separated from the surface of fine particles or fibers to cause cracks and clouding.
Further, U.S. Pat. No. 4,539,061 proposes a technique of forming a monomolecular film on a substrate by chemical adsorption.
Furthermore, in U.S. Pat. No. 4,761,316, the present inventors have proposed the formation of a protective film on a surface of a magnetic recording medium by chemical adsorption of a silane surface active agent.